1
0
n
235
92
U
236
92
U
140
55
Cs
93
37
Rb
3
1
0
n
NUCLEAR FISSION
DOE-HDBK-1019/1-93
Atomic and Nuclear Physics
NP-01
Page 48
Rev. 0
NUCLEAR FISSION
Nuclear fission is a process in which an atom splits and releases energy, fission
products, and neutrons. The neutrons released by fission can, in turn, cause
the fission of other atoms.
EO 4.1
EXPLAIN the fission process using the liquid drop model
of a nucleus.
EO 4.2
DEFINE the following terms:
a.
Excitation energy (E )
exc
b.
Critical energy (E
)
crit
EO 4.3
DEFINE the following terms:
a.
Fissile material
b.
Fissionable material
c.
Fertile material
EO 4.4
DESCRIBE the processes of transmutation, conversion,
and breeding.
EO 4.5
DESCRIBE the curve of Binding Energy per Nucleon
versus mass number and give a qualitative description of
the reasons for its shape.
EO 4.6
EXPLAIN why only the heaviest nuclei are easily fissioned.
EO 4.7
EXPLAIN why uranium-235 fissions with thermal
neutrons and uranium-238 fissions only with fast neutrons.
Fission
In the fission reaction the incident neutron enters the heavy target nucleus, forming a compound
nucleus that is excited to such a high energy level (E > E ) that the nucleus "splits"
exc
crit
(fissions) into two large fragments plus some neutrons. An example of a typical fission
reaction is shown below.
A large amount of energy is released in the form of radiation and fragment kinetic energy.
